Definitions

It is imperative to learn these

Unit 1

Atomic Number - Number of protons in an atom of an element (1)- don't get confused with RAMMass Number - The number of protons and neutrons in an atom of an element (1)- don't get confused with RAMIsotope - Atom of the same element but with different amounts of neutrons (1)Relative Atomic Mass - The average mass (1) of an atom of an element compared to 1/12th the mass of Carbon-12 (1)Relative Molecular Mass - The average mass (1) of a molecule compared to 1/12th the mass of Carbon-12 (1)Avogadro Constant - The amount of carbon-12 atoms in 12 grams of carbon-12 (1)Molarity - The concentration of a solution measured in moles per decimetre cubed (1)Percentage Yield - The percentage of the actual mass of the product over the theoretical mass (1)Percentage atom economy - The percentage of the mass useful products over the entire mass(1)Metallic Bonding - A giant lattice of positive ions (1) surrounded by a sea of delocalised electrons (1)Ionic Bonding - Positive ions and negative ions (1) attracted to each other by strong electrostatic forces (1)Covalent Bonding - When a pair of electrons is shared (1) with one electron coming from both (1)Dative Covalent Bonding - When the shared pair of electrons (1) come from one of the atoms sharing (1)Electronegativity - The ability of an atom to attract electron density (1) towards itself in a covalent bond (1)Polar Molecule - Electrons are unevenly spread (1) due to partial charge differences (1)Fractional Distillation - When crude oil is heated (1) separating it into it's independent fractions(1)Fraction - A hydrocarbon with a certain length carbon chain (1)Hydrocarbon - A compound containing only hydrogen and carbon (1)Homologous Series - A family of carbon compounds that contain the same functional group (1)Functional Group - Part of a carbon compound that is responsible for the chemical reactions which occur (1)Structural Isomers - Compounds that have the same molecular formula (1) but different structural formula (1)Chain Isomers - Compounds that have the same molecular formula (1) but different length carbon chains (1)Positional Isomers - Compounds that have the same molecular formula (1) but the functional group is in a different place on the carbon chain(1)Functional Group Isomers - Compounds with the same molecular formula (1) but different functional groups (1)- generally alkenes and cycloalkanesCracking - The breaking (1) of a larger, less in demand fraction into smaller, more in demand fractions (1)Homolysis (Homolytic Fission) - Equal splitting of a covalent bond (1) producing free radicalsHeterolysis (Heterolytic Fission) - Unequal slitting of a covalent bond (1) producing ionsFree Radical - Species that has an unpaired electron (1)

Unit 2

Reduction:a gain of electrons (1)Reducing agent: something that donates electrons (1)Polymerisation: the joining together of monomers (1) to form long chains (1)Electrophile:electron pair acceptor (1)Addition: reaction which increases number of substituents (1)Dehydration: the elimination of water from a compound (1)Structural isomers: compounds with the same molecular formula (1) but different structural formulae (1)Position isomers:compounds with the same molecular formula (1) but different structures due to different positions of the same functional group on the same carbon skeleton (1)Biofuel: a fuel made from plants or organic matter (1)Oxidation: loss of electrons (1)Oxidation state: the charge on the ion or element or atom (1)Oxidising agent: a substance which accepts electrons (1)Dynamic equilibrium: rate of forward reaction = rate of backward reaction (1)concentrations of reactants and products remain constant (1)Compromise temperature: balance between rate and yield (1)Activation energy:minimum energy (1) to start a reaction (1)Catalyst: speeds up a reaction but is chemically unchanged at the end (1)Mean bond enthalpy: enthalpy change when a bond is broken (1) in a covalent bond (1)averaged over all molecules containing that bond(1)Standard enthalpy of formation: enthalpy change when 1 mol of compound (1) is formed from its elements (1) all substances in their standard states (1)Standard enthalpy of combustion: enthalpy change when 1 mol of a substance (1) is completely burned in oxygen(1) under standard conditions (1)Enthalpy change: heat energy change (1) under constant pressure (1)Stereoisomers: compounds with the same structural formula(1) but a different arrangement of atoms in space (1)Rate of reaction: the change in concentration per unit of time (1)Nucleophile: an electron pair donor (1)Carbon neutral:an activity which has no net carbon emissions to the atmosphere (1)Hess’s Law: enthalpy change is independent of the route taken (1)

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Chubby Revision: A Level students revision for Chemistry, Physics, Geography and Maths